From: Lin Ming <ming.m.lin@xxxxxxxxx> Examines the return object from a call to acpi_evaluate_object. Any Index or RefOf references are automatically dereferenced in an attempt to return something useful (these reference types cannot be converted into an external ACPI_OBJECT.) Lin Ming, Bob Moore. http://bugzilla.kernel.org/show_bug.cgi?id=11105 Signed-off-by: Lin Ming <ming.m.lin@xxxxxxxxx> Signed-off-by: Bob Moore <robert.moore@xxxxxxxxx> Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx> Signed-off-by: Len Brown <len.brown@xxxxxxxxx> --- drivers/acpi/namespace/nsxfeval.c | 79 +++++++++++++++++++++++++++++++++++++ 1 files changed, 79 insertions(+), 0 deletions(-) diff --git a/drivers/acpi/namespace/nsxfeval.c b/drivers/acpi/namespace/nsxfeval.c index 38be586..f3cc376 100644 --- a/drivers/acpi/namespace/nsxfeval.c +++ b/drivers/acpi/namespace/nsxfeval.c @@ -45,9 +45,14 @@ #include <acpi/acpi.h> #include <acpi/acnamesp.h> #include <acpi/acinterp.h> +#include <acpi/amlcode.h> #define _COMPONENT ACPI_NAMESPACE ACPI_MODULE_NAME("nsxfeval") + +/* Local prototypes */ +static void acpi_ns_resolve_references(struct acpi_evaluate_info *info); + #ifdef ACPI_FUTURE_USAGE /******************************************************************************* * @@ -69,6 +74,7 @@ ACPI_MODULE_NAME("nsxfeval") * be valid (non-null) * ******************************************************************************/ + acpi_status acpi_evaluate_object_typed(acpi_handle handle, acpi_string pathname, @@ -283,6 +289,10 @@ acpi_evaluate_object(acpi_handle handle, if (ACPI_SUCCESS(status)) { + /* Dereference Index and ref_of references */ + + acpi_ns_resolve_references(info); + /* Get the size of the returned object */ status = @@ -352,6 +362,74 @@ ACPI_EXPORT_SYMBOL(acpi_evaluate_object) /******************************************************************************* * + * FUNCTION: acpi_ns_resolve_references + * + * PARAMETERS: Info - Evaluation info block + * + * RETURN: Info->return_object is replaced with the dereferenced object + * + * DESCRIPTION: Dereference certain reference objects. Called before an + * internal return object is converted to an external union acpi_object. + * + * Performs an automatic dereference of Index and ref_of reference objects. + * These reference objects are not supported by the union acpi_object, so this is a + * last resort effort to return something useful. Also, provides compatibility + * with other ACPI implementations. + * + * NOTE: does not handle references within returned package objects or nested + * references, but this support could be added later if found to be necessary. + * + ******************************************************************************/ +static void acpi_ns_resolve_references(struct acpi_evaluate_info *info) +{ + union acpi_operand_object *obj_desc = NULL; + struct acpi_namespace_node *node; + + /* We are interested in reference objects only */ + + if (ACPI_GET_OBJECT_TYPE(info->return_object) != + ACPI_TYPE_LOCAL_REFERENCE) { + return; + } + + /* + * Two types of references are supported - those created by Index and + * ref_of operators. A name reference (AML_NAMEPATH_OP) can be converted + * to an union acpi_object, so it is not dereferenced here. A ddb_handle + * (AML_LOAD_OP) cannot be dereferenced, nor can it be converted to + * an union acpi_object. + */ + switch (info->return_object->reference.opcode) { + case AML_INDEX_OP: + + obj_desc = *(info->return_object->reference.where); + break; + + case AML_REF_OF_OP: + + node = info->return_object->reference.object; + if (node) { + obj_desc = node->object; + } + break; + + default: + return; + } + + /* Replace the existing reference object */ + + if (obj_desc) { + acpi_ut_add_reference(obj_desc); + acpi_ut_remove_reference(info->return_object); + info->return_object = obj_desc; + } + + return; +} + +/******************************************************************************* + * * FUNCTION: acpi_walk_namespace * * PARAMETERS: Type - acpi_object_type to search for @@ -379,6 +457,7 @@ ACPI_EXPORT_SYMBOL(acpi_evaluate_object) * function, etc. * ******************************************************************************/ + acpi_status acpi_walk_namespace(acpi_object_type type, acpi_handle start_object, -- 1.5.5.1 -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
